1. Field of the Invention
This disclosure relates to an electrophoretic display device (EPD) and a method of manufacturing and repairing the EPD, and more particularly to an EPD which can prevent generation of cracks in a protection layer during a repair process, and a method of manufacturing and repairing the EPD.
2. Discussion of the Related Art
In general, electrophoretic display devices (EPDs) are flat display devices using electrophoresis (a phenomenon that charged particles are moved toward anode or cathode in an electric field) and need no external light source, exhibit a superior reflection rate and superior flexibility and portability, and are light weight.
The EPD is a reflection type display, in which electrophoretic suspension particles are driven by coating a base film that is thin and easy to bend like paper or plastic, with a transparent conductive film. The EPD is expected to be highlighted as a next generation electric paper.
An EPD according to conventional technology is described with reference to FIG. 1A. FIG. 1A is a cross-sectional view schematically illustrating a conventional EPD.
Referring to FIG. 1A, a gate line (not shown) and a gate electrode 13a are formed on a substrate 11. A common electrode 15 is arranged by being separated from the gate line and in the same direction as the gate line. Then, a gate insulation layer 17 is formed on the substrate 11 on which the gate line and the gate electrode 13a are formed. A semiconductor pattern 19 is formed on the gate insulation layer 17 corresponding to the gate electrode 13a. 
A data line 21 defining a pixel area P by crossing the gate line, a source electrode 21a extending from the data line 21, and a drain electrode 23 separated a predetermined distance from the source electrode 21a and simultaneously protruding toward the pixel area P are formed. The semiconductor pattern 19, the source electrode 21a, the drain electrode 23, and the gate electrode 13a constitute a thin film transistor (TFT) portion.
Next, a protection layer 25 is deposited on the overall surface of the substrate 11 where the source electrode 21a, the data line 21, and the drain electrode 23 are formed. Then, the protection layer 25 is selectively patterned to form a drain contact hole 27 that exposes the drain electrode 23. The protection layer 25 is formed by depositing an organic layer that is a low dielectric, for example, photoacrylate, on a structure in which the electrodes are overlapped with one another.
Then, a transparent electrode layer is deposited on the protection layer 25 including the drain contact hole 27 and patterned to form a pixel electrode 31. The pixel electrode 31 is connected to the drain electrode 23 via the drain contact hole 27. Also, the pixel electrode 31 is overlapped over the gate line and the data line 21 in the pixel area P where the gate line and the data line 21 are defined by crossing each other.
An electrophoretic film 33 is deposited on the substrate 11 including the pixel electrode 31. The electrophoretic film 33 includes a polymer binder and capsules 30 containing electric ink. The electronic ink within the capsule 30 includes white ink 33a and black ink 33b. Also, the white ink 33a and the black ink 33b distributed in the electrophoretic film 33, respectively, are charged into a positive charge and a negative charge.
A common line (not shown) is formed on the electrophoretic film 33 so that an EPD may be completed. The EPD is a reflection type display device and, to increase a reflectance, the pixel electrode 31 is formed to overlap over the gate line and the data line 21 in the pixel area P. As the pixel electrode 31 is overlapped with the gate line or the data line 21, capacitance generated therebetween increases which affects a driving voltage of the pixel electrode 31.
Thus, as the protection 25 located between the pixel electrode 31 and the gate line or the data line 21 is relatively thickly formed, signal interference between the pixel electrode 31 and the gate line or the data line 21 may be minimized.
When the common electrode 15 is disconnected, a repair process is performed. In the repair process, the common electrode 15 that is disconnected is cut off by emitting a laser beam onto the gate insulation layer 17 and the protection layer 25 corresponding to the common electrode 15. However, referring to FIG. 1B, when a laser beam is emitted in an area A of the protection layer 25 corresponding to the common electrode 15, due to the thickness of the protection layer 25, cracks may be generated in the protection layer 25 to which the laser beam is emitted so that the gate line and the data line 21 may be disconnected.